Precision inertial navigation systems can eliminate the need for gimbals by supporting the inertial sensor assembly with a spherically shaped gas supported bearing. During the flight of a craft, the angular position of the inertial sensor assembly (sometimes also referred to as the attitude, or roll, pitch and yaw of the inertial sensor assembly) relative to the frame of the craft must be monitored at all times by an optical imaging system that images a reference surface pattern on the surface of the spherically shaped gas supported bearing. The gas supported bearing allows rotation of the inertial sensor assembly in all axes without physical contact between an optical sensor in the optical imaging system and the assembly.
The optical sensor in the optical imaging system of such a precision inertial navigation system generates image signals of at least a portion of a reference surface pattern on the surface of the spherically shaped gas supported bearing. When an area of the reference surface pattern on the surface of the bearing is imaged, the location of the imaged area is determined by comparing the imaged area with a map of the pattern on the surface of the object. The inertial navigation system determines the rotation of the imaged area by comparing the angle of the pattern of the imaged area with a map of the pattern on the surface of the object. In this manner, the angular position of a rotating object is disclosed.
In other applications, an optical sensor in the optical imaging system is used to image the surface pattern that is patterned on the surface of objects that are moved through the line of sight of the optical sensor. For example, in a manufacturing assembly line, objects may be scanned to determine a position of the object, and a robotic system down-line from the optical imaging system and in communication with the optical imaging system is implemented to reposition the object if necessary.
The reference surface pattern is typically an array of symbols or shapes that are on the surface of the gas supported bearing or other object. The number of shapes and complexity of the shapes that are patterned on the surface of the spherically shaped gas supported bearing constrain the accuracy of the reading of the optical sensor and ultimately, of the inertial navigation system. The number of shapes and complexity of the shapes that are patterned on the surface of the assembly line objects constrain the accuracy of the reading of the optical sensor and ultimately, of the position of the object in the assembly line.